Flow control baffle for a bin unloader

ABSTRACT

A flow control baffle is disposed over a conveyor operating in a channel pit at the bottom of a storage bin. The baffle extends upward into the bin and has inclined baffle walls which channel the stored material around the sides of the baffle into the conveyor. The baffle has a bottom surface disposed over the conveyor and has elongated ribs extending below the bottom surface to establish the level of stored material in the conveyor. A vibration motor assembly is used to agitate the baffle independently of the conveyor.

United States Patent Hammond FLOW CONTROL BAFFLE FOR A BIN UNLOADER 1 1Feb. 22, 1972 3,185,321 .5/1965 Kemp ..214/17 R 2,926,961 3/1960Dieboid.. .....214/l7 R X 3,401,787 9/1968 Vaka ..2l4/l7 DA X PrimaryExaminer-Robert G. Sheridan AttorneyAndrus, Sceales, Starke & Sawall [57] ABSTRACT A flow control baffle is disposed over a conveyor operatingin a channel pit at the bottom of a storage bin. The baffle extendsupward into the bin and has inclined baffle walls which channel thestored material around the sides of the baffle into the conveyor. Thebaffle has a bottom surface disposed over the conveyor and has elongatedribs extending below the bottom surface to establish the level of storedmaterial in the conveyor. A vibration motor assembly is used to agitatethe baffle independently of the conveyor.

8 Claims, 6 Drawing Figures PATENIEBFEB 22 I972 SHEET 1 OF 2 FLOWCONTROL BAFFLE FOR A BIN UNLOADER BACKGROUND OF THE INVENTION Thisinvention relates to conveyor bin unloader systems and more particularlyto flow controls for conveyor unloader systems.

Storage bins or hoppers, such as would be used for storing salt,powders, or similar friable materials, commonly have conveyor unloadersat their bottoms. Most unloader systems require some means ofcontrolling material flow onto the conveyor in the bin such as baffledevices.

Such devices have been provided but have inadequacies. For instance,some materials are reluctant to flow and therefore are difficult tounload uniformly. Under some conditions, such as with frozen or cakedstored material, the conveyor unloading operation can be stopped by theresistance to flow around the baffle.

Another disadvantage with some prior baffles are that they loadeddirectly on top of the conveyor. The weight of the stored material wasthen carried by the conveyor in these systems, and thus requiredhigherstarting torque motors than otherwise. Further, it was found thatsomematerials would not freely fall into the conveyor with such baffles,because the material tended to arch over and compact. Uniform unloadingwas thus impaired.

Other control baffles were devised which contemplated solving suchdifficulties. These still had problems. The latter baffles were disposedover the conveyors and directed material flow around the sides of thebaffles to the conveyors. This design tended to relieve the conveyors ofthe full weight of the stored material. However, material still piled upon the conveyors, adding unnecessary weight and creating nonuniformdischarge from the bins. Further, the stored material tended to flowfirst from one part of the bin, thus emptying the bin to unequal levelsand creating unequalstresses on the storage structure walls.

The problem of reluctant flowage into the conveyor has been attacked byproviding agitating apparatus with or separate from the baffleassemblies. However, these generally operated from the conveyor drivesand did not provide full discharge flow control by the agitation in thebin.

SUMMARY OF THE INVENTION The invention is directed to solving the abovedifficulties and advances beyond the previous development to providefurther advantageous features. Various advantages will be apparent fromthe drawings and description.

The invention provides a means of controlled discharge of storedmaterial onto a conveyor system. The structure of the invention relievesthe conveyor system from extra pileup of stored material and providesuniform and more precisely controlled flow to the conveyor.

These advantages are accomplished by an assembly including an elongatedload control baffle which-has inclinedbaffle plates functioning tochannel material flow around the sides of the control baffle to theconveyor. The'baffle is disposed over a channel in which a conveyoroperates and the baffle plates are spaced from the edges of the conveyorchannel along its length. The body of the control baffle is disposedover the conveyor to relieve it from the weight of the stored materialin the bin.

To further avoid pileup of excess material on the conveyor, the bafflehas a bottom surface disposed over the conveyor along its length at apredetermined-level in accordance with the desired discharge rate forunloading. However, for certain kinds of conveyor unloaders, such asvibratory unloaders, a mere bottom surface on the baffle, whiledetermining the proper level of the material in the conveyor, will tendto compact the material beneath it and thus add weight on the conveyorand cause irregular flow out of the bin.

To control the material flow from the bin even more accurately. as wellas to lessen the power requirements for the conveyor unloader drive, thebaffle control of the invention has elongated, narrow ribs extendingalong a substantial length of the bottom surface on the baffle. The ribsdetermine the level of the stored material which has entered theconveyor, but the compacting action by the operation of the conveyor isavoided.

A further advantageous feature of the ribs is that they may be shaped inaccordance with the flow characteristics of the stored material and thedesired control of the level of material in the entire bin. When theribs are tapered or similarly shaped, they may be used to establish ahigher level at the discharge end of the conveyor than at the insideend. Thus, proper shaping of the ribs will permit continuous flowage ofmaterial along the entire length of the bin rather than from only oneportion at a time. This will be done when it is desired to maintain auniform level of material in the bin structures.

A further feature of the baffle control of the invention is that itincludes a vibrator system which may be used to agitate caked or frozenmaterials or to otherwise more accurately control the flow of anymaterial stored in a bin or hopper. This feature is not dependent on theoperation of the conveyor unloader and can be used with any typeconveyor.

The agitator structure is integral with the control baffle and iscomprised of inwardly inclined upper surface walls extending upwardly toa peak above the conveyor. A vibrator motor and assembly is attached tothe baffle and serves to vibrate the baffle to agitate the storedmaterial and cause it to flow around the sides and around the baffleplates to the conveyor. The rate of vibration can be controlled tofurther determine the discharge rate of the stored materials, or thevibration can be terminated when increased flow is not needed.

Thus, the invention provides various advantages of precise flow controlunder varied conditions and serves to lessen the power requirements forthe unloader conveyor drive.

The figures illustrate the best embodiments presently contemplated bythe inventor.

In the drawings:

FIG. 1 is a side elevational view of'the bin with FIG. 1;

FIG. 4 is a bottom plan view of the baffle; section to show theinvention;

FIG. 2 is a perspective view of the invention with parts in section;

FIG. 3 is a section taken along line 3-3 of FIG. 1;

' FIG. 4 is a bottom plan view of the baffle;

FIG. 5 is a side elevational view ofa modified baffle; and a sideelevational view of another modified baffle.

DESCRIPTION Shown in the figures is a storage bin 1 supported on afoundation 2 and having a cylindrical sidewall 3 with a roof 4 on topforming a generally enclosed structure for storing a material 5, such assalt, powders or grain, or other generally friable materials. Wall 3 androof 4 may be constructed of glass lined metal sheets and are shownaccordingly.

In order to provide room for unloading means, foundation 2 has an opentop channel 6 which is an elongated tunnel through the foundation andmay have side recesses for adequate operating room. The sidewalls ofchannel 6 define lengthwise top edges 7 and 8 along the length of thechannel, which extends from wall 3, along a diameter to an opening 9 inthe bin. Material 5 may be discharged through opening 9 and a conveyordischarge end 10.

The unloader system is disposed in channel 6 and includes a conveyor 11and a control baffle 12 which operate to discharge material 5 from end10 at a controlled rate. In general, baffle 12 channels the flow ofmaterial to conveyor 11, which in turn carries the material to theoutside.

Conveyor 11 is shown as the vibrator type commonly in use as binunloaders. Well-known endless belt conveyors could also be used-with theinvention, although there are special advantages for the invention inuse with the vibrato'r'type. As in the usual construction of conveyor11, a flat bottom, U- shaped metal pan 13 extends nearly the length ofchannel 6,

occupying the top portion of the space provided by the recess andserving as the unloading member. Having a flat bottom 14 and sidewalls15 extending upward therefrom at an incline or vertically as desired,pan 13 is utilized to hold a portion of material 5 above the floor ofchannel 6 but beneath channel edges 7 and 8.

To avoid spillage into the recess, sidewalls have outwardly flanged lips16 fully along their respective top edges. correspondingly, a pair ofdownwardly flanged, metal floor strips 17 are attached by suitable meansto foundation 2, fully along channel 6 and extend over the recess beyondedges 7 and 8 and over flanged lips 16 of conveyor pan 13. A liner l8,completing the assembly, extends across the width of channel 6 and isbonded or clamped to both floor strips 17 along their full lengths.Being flexible and of sufficient size, liner l8 suspends from strips 17and rests against the surfaces of pan sidewalls l5 and flat bottom 14 toassume a corresponding flat bottom U-shape. This structure avoidsspillage and permits pan movement relative to channel 6, liner l8 andthe stored material 5 being carried by the pan. Other known pan and panattachment assemblies are equally suitable for use with the invention.

For purposes of vibrating conveyor 11, a motor and crank assembly 19 aredisposed at opening 9. Assembly 19 may be any conventional variety usedin vibratory conveyor systems and operates a crank 20, which isconnected to pan 13 for shaking the pan. The pan is pivotally supportedover the bottom of channel 6 by pivotal supports 21 connecting pivotallybetween the bottom of the pan and box frame support 22 disposed on thebottom of the channel.

Any suitable switch control 23, shown schematically connected to themotor of assembly 19, may be used to control the vibration of pan 13. Itis contemplated that the unloading operation will be initiated andterminated by use of switch 23.

Flow control baffle 12 controls the flow of material 5 to conveyor 11 inaccordance with the invention. The body of baffle 12 is elongated withinclined sides and any frame construction suitable to provide thisconfiguration may be utilized. In the example shown, a frame 24 has aplurality offrame sections, each with a bottom flat bar 25 being weldedto lower side flat bars 26 which are in turn welded to top side flatbars 27. Flat bars 27 are also welded together at the top to complete afive-side box frame section. The sections are spaced apart in accordancewith structural requirements of stored material weight in any particularbin.

The shape of box frame 24 determines the body shape for baffle 12 andmay be functionally divided into two body sections, a lower controlbaffle section at 28 and an integral, upper agitator, baffle section at29. In lower section 28, lower flat bars 26 are inclined upwardly andoutwardly from bottom flat bar 25. which is horizontal To provide a peakat the top of baffle 12. top flat bars 27 are inclined upwardly andinwardly from the outer ends ofbars 26.

The baffle surfaces are provided on the box frame sections, and includeagitator baffle plates 30 connected to the outside edges of upper flatbars 27 on both sides of the baffle. Plates 30 are joined together as bywelds at their tops. For channeling the flow into pan 13, a pair ofcontrol baffle plates 31 are connected to flat bars 26 on both sides ofbaffle 12. Plates 30 and 31 are elongated and together provide a fullflat surface along the length of baffle 12.

As control baffle 12 is disposed over channel 6, plates 31 and theirsupportive frame sections are disposed adjacent edges 7 and 8 of channel6 and extend to above foundation 2. The lower ends of plates 31 extendover channel 6 and conveyor 11, leaving a space between edges 7 and 8and control baffle plates 31 through which portions of material 5 flowin operation. The space between edges 7 and 8 and baffle plates 31 ispredetermined to correspond with the desired flow rate of conveyor 11,and may be a uniform distance or a varied spacing along the length ofbaffle 12 as desired.

To determine the level of material in conveyor 11, a flat bottom plate32 is provided for baffle 12 and extends fully across the bottom of thebaffle to be secured as by welds to bottom flat bars 25. Bottom plate 32is elongated and secured along its lengthwise edges by suitable welds tothe bottom edges of baffle plates 31. In this construction, the flatbottom surface of bottom plate 32 lies horizontally over conveyor 11,being spaced a predetermined distance above the bottom of channel 6 inaccordance with the desired capacity and discharge rate of the conveyor.Bottom plate 32 overlies a substantial portion of conveyor 11 and ispositioned between foundation edges 7 and 8. Material will flow betweenbaffle plates 31 and edges 7 and 8 to conveyor 11 in operation.

In accordance with the invention, it is desired to limit the materiallevel in conveyor 11 without compacting it. The invention inhibits thematerial from building up fully to the bottom plate 32. For thispurpose, plate 32 has vertical ribs 33 extending longitudinally over itsbottom surface. Ribs 33 may be flat bars attached on plate 32 to dependvertically downward with narrow bottom edges facing conveyor 11. Thedistance downward which ribs 33 extend determines the upper level thatthe material in pan 13 may reach. In the example shown in FIGS. 1-4,this distance is shown as being uniform among the ribs, and is the samealong the full length of baffle 12. The distance is predetermined inaccordance with the flow metering desired. Ribs 33 are spaced apart topresent a small surface area facing the pan, and primarily with avibratory conveyor 11, the motion of pan 13 will drive the materialtherein against only the narrow edges of ribs 33, thereby avoidingcompaction of the material. For this purpose the ribs should be asnarrow as their structural limitations permit.

As another feature of the invention, agitator baffle section 29 isdesigned to loosen the stored material 5 in the bin especially where thematerial is reluctant to flow and whenever an increased flow aroundcontrol baffle plates 31 is desired. To provide this feature, baffle 12has a vibrator 34 which causes the baffle to vibrate largely in a planeparallel to foundation 2.

Vibrator 34 may be of any common variety and is shown as a double shaft,electric motor 35, mounted vertically within baffle 12 and having ahorizontal eccentric weight 36 on each motor shaft. Motor 35 is mountedat the center of baffle 12 on a rigid plate 37 which is in turn mountedon the appropriate frame bars of the baffle.

Shown schematically, switch 38 is situated in an accessible placeoutside bin 1 and is electrically connected to motor control 39, alsoshown schematically. Any suitable switch and control may be used, and incertain applications it would be advisable to include a variable speedcontrol in motor control 39 in order to easily increase or decrease theagitation of baffle 12. By this means, some materials may be caused toflow at a varying preset rate into conveyor 11. The motion of eccentricweights 36 will tend to shake plate 37 and baffle 12 primarily back andforth transversely to the length of baffle 12, the magnitude anddirection of the motion being determined by the design of the structurewhich mounts the baffle in the bin.

To permit such vibration in this plane, while supporting the baffleunder the usual weight of material 5, baffle 12 is mounted on severalshock mounts 40 to foundation 2. Shock mounts 40 are of a common saddleelastomeric mount construction and are each bolted to a baffle supportchannel 41 suitably secured to baffle 12. Support channels 41 are boltedto a saddle 42 which is in turn supported on an elastomeric mount 43held on a base 44 by a cast housing 45 extending around elastomericmount 43. A nut, bolt and washer assembly 46 connecting mount 43 andsaddle 42 complete a shock mount 40 which is suitably mounted as bybolts on foundation 2 on a side of channel 6.

In operation of vibrator 34, eccentric weights 36 will rock baffle 12back and forth across channel 6 on shock mounts 40.

This motion can be used to increase flow into conveyor 11, as desired.

OVERALL OPERATION A loaded bin 1 is partially unloaded by operatingconveyor 11 which will begin vibrating its pan 13 to move any materialtherein toward discharge end 10. Since baffle 12 relieves conveyor 11 ofthe weight of material 5, start-up is no problem. As pan 13 is vibratedand the stored material in the pan moves through door 10, material inbin 1 will begin to flow around baffle 12 wherever there is room in theconveyor. Baffle plates 31 on both sides of the baffle will channel thematerial through the space above ledges 7 and 8 to liner 18 and pan 13.This space is sufficiently large to allow the flow characteristics ofthe stored material to determine its rate of entry onto liner 18 of theconveyor.

Further control is provided by ribs 33, which in the operation ofconveyor 11 level off the material in pan 13. For most applications, itwill be desired to provide a space between baffle plates 31 and ledges 7and 8 sufficient to permit filling to the level of ribs 33.

If the material is not flowing smoothly, or at a sufficient rate,vibrator 34 may be started to put baffle 12 in motion so that agitatorbaffle plates 30 rock against the stored material to loosen it and causeit to flow around control baffle plates 31.

MODIFICATIONS The shape and size of the ribs on bottom plate 32 may bevaried to vary the flow metering characteristic of baffle l2, and toobtain more uniformity of flow along the length of channel 6. FIG. 5shows an example of a narrow tapered rib 47. As before, a number of ribs47 could be provided from flat bars and secured to bottom plate 32 alongthe full length of baffle 12, with a narrow edge facing the conveyorbottom. The taper is from the front of baffle 12 at end to a greatersize at the back. This configuration will determine a lower level inconveyor 11 at the back than further forward, and as the material movesforward in the conveyor, there is room underneath ribs 47 for morematerial to flow from bin 1. Thus, material will tend to flow aroundbaffle plates 31 into the conveyor all along channel 6, rather thanmainly at the back portion, for a more uniform leveling ofthe load inthe bin.

FIG. 6 shows a similarly tapered rib 48, which taper is accomplished insteps in this embodiment. A rib 48 is otherwise the same in structureand operation as a rib 47.

Thus, the structures described are examples of the invention whichprovide advantageous features of flow metering and load relief for aconveyor unloader in a storage bin.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims which particularly point outand distinctly claim the subject matter which is regarded as theinvention.

lclaim:

1. In an unloader for unloading friable material stored in a bin, thebin having an elongated channel on its bottom, the unloader including aconveyor having an elongated unloading member operably extending withinthe channel; a flow control baffle supported by the bin over theelongated channel and conveyor, the baffle having at least one controlbaffle surface spaced from an adjacent lengthwise edge of the channel,the baffle having further a bottom surface which overlies acorresponding substantial area of the unloading member; and a pluralityof elongated ribs extending from the bottom surface a distance beneaththe bottom surface predetermined in accordance with the desired level ofloading onto said unloading member of said friable material between saidcontrol baffle surface and said channel lengthwise edge.

2. The structure of claim 1, wherein the ribs are spaced from each otherand have thin edges facing the unloading member at said predetermineddistance from the bottom surface of the baffle, the spacing of the ribsbeing substantially greater than the width of said thin edges.

3. The structure of claim 1, wherein the ribs are flat bars attached tothe bottom surface with thin ed es of the bars facin down, and the ribsare spaced to provi e only lnsubstantia total surface area of the thinedges overlying the unloading member.

4. The structure of claim 1, wherein the baffle has two elongated bafflesurfaces, each extending longitudinally along an opposite lengthwiseedge of the channel, the baffle surfaces in their lateral dimensionbeing oppositely inclined downwardly and inwardly toward the channel toextend from above to below the lengthwise edge of the channel, and thebottom surface is attached between the bottom lengthwise edges of thebaffle surfaces.

5. The structure of claim 4, wherein the baffle surfaces are in generallongitudinal alignment with their respective lengthwise edges of thechannel; the ribs are flat bars attached to the bottom surface with thinedges facing the unloading.

member in the channel; and at least some of the ribs extend in generallongitudinal alignment with each baffle surface.

6. The structure of claim 5, wherein the unloading member extends fromthe back of the bin to an unloading end, and said ribs in longitudinalalignment with the baffle surfaces extend below the bottom surface apredetermined distance which is varied in accordance with the proximityto said unloading end, the predetermined distance being greater towardthe back to provide uniform material flow onto the unloading memberalong its length.

7. A control baffle for a bin unloader lying in an elongated recessedchannel at the bottom of a bin adapted for storing a friable material,the baffle being disposed in longitudinal alignment with the channel andhaving an elongated bottom surface overlying the unloader and additionalbaffle surfaces which are in longitudinal alignment with an adjacentlengthwise edge of the channel, said additional baffle surfaces beinglaterally inclined downwardly and inwardly from above to below thelengthwise edge of the channel and providing a flow space between thechannel edge and the baffle, and elongated ribs depending from saidbottom surface for distances predetermined in accordance with thedesired level ofloading in the unloader, and said ribs extending inlongitudinal alignment with the channel edge.

8. The baffle of claim 7, wherein said flow space is uniform for thefull length of the channel edge, and the ribs are elongated flat barsattached with their thin edges facing down.

Patent No. 3,643,820

Inventor(s) Column 2,. line .37,

Column 2, lines 38-39 Column 2, line 4 (SEAL) Attest:

EDWARD M .FLETCHER,JR. Attesting Officer UNITED STATES PATENT OFFICECERTIFICATE OF CORRECTION Ronald W. Hammond It is certified that errorappears in the above-identified patent and that said Letters Patent arehereby corrected as shown below:

Cancel "Fig. 1" (second occurrence) and substitute therefor ----parts insection to show the invention--- Cancel "Fig. 4 is a bottom plan view ofthe baffle; section to show the invention;"

Cancel "a side elevational view of another modified baffle."

Insert a Figure 6 which reads:

---Fig. 6 is a side, elevational view of another modified baffle.---

Signed and sealed this 12th day 'of September 1972.

ROBERT GOTTSCHALK Commissioner of Patents F OHM Fit-10W! 10479)USCOMM-DC 6037 34 0 u s covrnnmzm murmur. orncrwas O-JEG'DJI

1. In an unloader for unloading friable material stored in a bin, thebin having an elongated channel on its bottom, the unloader including aconveyor having an elongated unloading member operably extending withinthe channel; a flow control baffle supported by the bin over theelongated channel and conveyor, the baffle having at least one controlbaffle surface spaced from an adjacent lengthwise edge of the channel,the baffle having further a bottom surface which overlies acorresponding substantial area of the unloading member; and a pluralityof elongated ribs extending from the bottom surface a distance beneaththe bottom surface predetermined in accordance with the desired level ofloading onto said unloading member of said friable material between saidcontrol baffle surface and said channel lengthwise edge.
 2. Thestructure of claim 1, wherein the ribs are spaced from each other andhave thin edges facing the unloading member at said predetermineddistance from the bottom surface of the baffle, the spacing of the ribsbeing substantially greater than the width of said thin edges.
 3. Thestructure of claim 1, wherein the ribs are flat bars attached to thebottom surface with thin edges of the bars facing down, and the ribs arespaced to provide only insubstantial total surface area of the thinedges overlying the unloading member.
 4. The structure of claim 1,wherein the baffle has two elongated baffle surfaces, each extendinglongitudinally along an opposite lengthwise edge of the channel, thebaffle surfaces in their lateral dimension being oppositely inclineddownwardly and inwardly toward the channel to extend from above to belowthe lengthwise edge of the channel, and the bottom surface is attachedbetween the bottom lengthwise edges of the baffle surfaces.
 5. Thestructure of claim 4, wherein the baffle surfaces are in generallongitudinal alignment with their respective lengthwise edges of thechannel; the ribs are flat bars attached to the bottom surface with thinedges facing the unloading member in the channel; and at least some ofthe ribs extend in general longitudinal alignment with each bafflesurface.
 6. The structure of claim 5, wherein the unloading memberextends from the back of the bin to an unloading end, and said ribs inlongitudinal alignment with the baffle surfaces extend below the bottomsurface a predetermined distance which is varied in accordance with theproximity to said unloading end, the predetermined distance beinggreater toward the back to provide uniform material flow onto theunloading member along its length.
 7. A control baffle for a binunloader lying in an elongated recessed channel at the bottom of a binadapted for storing a friable material, the baffle being disposed inlongitudinal alignment with the channel and having an elongated bottomsurface overlying the unloader and additional baffle surfaces which arein longitudinal alignment with an adjacent lengthwise edge of thechannel, said additional baffle surfaces being laterally inclineddownwardly and inwardly from above to below the lengthwise edge of thechannel and providing a flow space between the channel edge and thebaffle, and elongated ribs depending from said bottom surface fordistances predetermined in accordance with the desired level of loadingin the unloader, and said ribs extending in longitudinal alignment withthe channel edge.
 8. The baffle of claim 7, wherein said flow space isuniform for the full length of the channel edge, and the ribs areelongated flat bars attached with their thin edges facing down.